What Is Hemoglobin A1c?

Hemoglobin is the oxygen-carrying pigment that gives blood its red color and is also the predominant protein in red blood cells. About 90% of hemoglobin is hemoglobin A (the “A” stands for adult type). Although one chemical component accounts for 92% of hemoglobin A, approximately 8% of hemoglobin A is made up of minor components that are chemically slightly different. These minor components include hemoglobin A1c, A1b, A1a1, and A1a2. Hemoglobin A1c (HbA1c) is a minor component of hemoglobin to which glucose is bound. HbA1c also is sometimes referred to as glycated, glycosylated hemoglobin, or glycohemoglobin.

How the Test Works

The sugar in your blood is called glucose. When glucose builds up in your blood, it binds to the hemoglobin in your red blood cells. The A1c test measures how much glucose is bound.

Red blood cells live for about 3 months, so the test shows the average level of glucose in your blood for the past 3 months.

If your glucose levels have been high over recent weeks, your hemoglobin A1c test will be higher.

D-dimer

A D-dimer test is a blood test usually used to help check for or monitor blood clotting problems. A positive test means the D-dimer level in your body is higher than normal and suggests you might have blood clots.

What is being tested?

This test measures the amount of D-dimer, which is normally undetectable, in your blood. Blood clots form whenever a blood vessel is damaged, whether that’s by an injury or by atherosclerosis, or when blood flow is restricted, such as by a vessel being compressed for a long time. When you have an injury, your body creates a blot clot to stop blood from leaking out of your blood vessels. D-dimer is a type of protein your body produces to break down the blood clot.

High CRP levels can also indicate that there’s inflammation in the arteries of the heart, which can mean a higher risk of heart attack. However, the CRP test is an extremely nonspecific test, and CRP levels can be elevated in any inflammatory condition.

How does CRP test?

No special preparation is necessary for this test. You may eat normally on the day of the test.

A nurse or other health practitioner draws blood from a vein, usually on the inside of your elbow or the back of your hand:

First, they clean the skin over the vein with antiseptic. Next, they wrap an elastic band around your arm, causing your veins to bulge out slightly. The practitioner then inserts a small needle into the vein and collects your blood in a sterile vial.

After the nurse or health practitioner collects your blood sample, they remove the elastic band around your arm and ask you to apply pressure to the puncture site with gauze. They may use tape or a bandage to hold the gauze in place.